Our offices are 10 blocks up Fifth Avenue from Washington Square Park, whose gateway is a triumphal arch designed in the 1890s by Stanford White, flanked by two statues of George Washington, one as soldier, one as President. It’s an unsatisfactory gateway because it is undergoing what seems to be an eternal restoration and for years has been caged by a chainlink fence.

So I was walking around rather than through the arch one day in early September when I heard a sound that was at once familiar and incomprehensible. I looked to my right, and coming toward me were two police horses, side by side, panicked and galloping, fully caparisoned for duty, tethered nightsticks bouncing against their empty saddles. I jumped a low fence and got behind a tree. The horses clattered past and away across the sunny park as mothers snatched their children to safety.

Well, I thought, that’s the scariest thing I’m likely to see for a while. I watched police catch and subdue the horses while, off to the south, the towers of the World Trade Center glittered serenely in the late-summer sunlight.

A week later, coming through the park on another midday, looking for the thousandth time at the haze of smoke or dust in the empty south, I walked into a small crowd and discovered that the drab fence had been turned into a shrine. Scores of bouquets hung in its grid; hundreds of votive candles burned at its base, pale in the bright sunshine. On the fence, along with the flowers, were messages—not the heartbreaking family portraits posted everywhere begging for information about their subjects, but rather letters of thanks to firefighters, to police officers, to all the dead who had died trying to save people they’d never met. Above these transient messages was a permanent one, carved into the monument, a phrase of George Washington’s: “Let us raise a standard to which the wise and the honest can repair.” During our brief national history, a great many Americans have died trying to help people they never met.

Two days before the flowers came to the fence, I’d stood in a street near our office on the most beautiful morning since the world began: clear, cool, so immaculate that the north tower of the World Trade Center might have been its small, precise simulacrum in the souvenir plastic globes filled with glittering debris that tourists take home with them. But now there was an oblong hole canted across its whole face, black smoke fuming off the top.

The man next to me explained what I was seeing, and after a while I replied, “This happened before, in 1945. A bomber flew into the Empire State Building.” I sounded fatuous; what I’d meant to say was that although that incident had been horrible, it was far less horrible than it might have been, and perhaps this time too…

A quiet thump, like a book being tossed down on a table, and a black and orange explosion bulged out from the other tower. I thought it was because of the accident, the building burning inside (the plane itself was no more visible than the blade of a knife when it does its killing), but my neighbor said, “That was another plane that hit.”

And then the news of the Pentagon and of Flight 93 in Pennsylvania—whose passengers behaved with exactly the same gallantry as their forebears who went on past the seawall at Omaha Beach in the full realization of what it would cost them—and the strange, muffled city days, the weather still perfect, but the light, filtered by the smoke rising from downtown, now hard-edged, and volcanic, and unforgiving.

Of course, the country also saw those towers riding their gray roil earthward, taking with them a cargo of humanity in numbers that, as this issue goes to press, have not been fully tallied.

A while later, I realized that I’d just come to understand something that had puzzled me since I’d read it years before. Once, when another group of thugs were trying to put another democracy out of business, Edward R. Murrow watched incendiary bombs falling on nighttime London and wrote, “What a puny effort is this to burn a great city.” Puny? A quarter of London burned; tens of thousands died. But now I see that the word was very carefully chosen. Murrow had already described the carnage fully; here, he was succinctly expressing his contempt not for the skill but for the cause of those who had brought it on.

We have heard again and again that the towers were the “symbol of our capitalist system.” During the campaign that Murrow reported, St. Paul’s Cathedral, standing undamaged amidst ever-wider seas of rubble, became a symbol of embattled Britain. But if a Heinkel had happened to drop a lucky stick of bombs and brought St. Paul’s down, Nazi Germany would still be just as thoroughly vanished today.

Symbols are very important. But they’re never as important as what they symbolize.